If the area of a triangle is 15 cm and the height is 6cm what is the base

Write an explicit formula that represents the sequence defined by the following recursive formula:

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

What are the solutions of the following system? y=-2x^2 y=x-2